


incentive

by imposterhuman



Category: Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Alternate Universe - High School, Bucky Barnes & Steve Rogers Friendship, Established Bucky/Natasha, F/M, Fluff, Happy Ending, M/M, Multi, Polyamory, Protective Steve Rogers, Steve Rogers & Tony Stark Friendship, Tutoring
Language: English
Status: Completed
Published: 2020-06-29
Updated: 2020-06-29
Packaged: 2021-03-04 00:01:25
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,500
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24984250
Author URL: https://archiveofourown.org/users/imposterhuman/pseuds/imposterhuman
Summary: If there was a hell, Bucky was pretty sure he was going to end up there for pining after his best friend’s adopted brother. Tony had only been with the Rogers family since his parents’ deaths a few months prior, but he knew that Sarah and Steve already viewed him as part of the family. They definitely wouldn’t take kindly to Bucky, the resident bad boy and all around terrible influence, corrupting Tony’s innocent nerdiness.At least Natasha was on his side. It barely mattered, since Bucky could hardly see Tony agreeing to date one of them, much less both of them, but it was the thought that counted.
Relationships: James "Bucky" Barnes/Natasha Romanov, James "Bucky" Barnes/Natasha Romanov/Tony Stark, James "Bucky" Barnes/Tony Stark, Natasha Romanov/Tony Stark
Comments: 7
Kudos: 269





	incentive

**Author's Note:**

> for anon who wanted a best friend's sibling au for winterironwidow
> 
> enjoy!!

If there was a hell, Bucky was pretty sure he was going to end up there for pining after his best friend’s adopted brother. Tony had only been with the Rogers family since his parents’ deaths a few months prior, but he knew that Sarah and Steve already viewed him as part of the family. They definitely wouldn’t take kindly to Bucky, the resident bad boy and all around terrible influence, corrupting Tony’s innocent nerdiness. 

At least Natasha was on his side. It barely mattered, since Bucky could hardly see Tony agreeing to date one of them, much less both of them, but it was the thought that counted. 

“Pining after Tony again?” his girlfriend asked, combing her hand through his hair.

Bucky made a helpless noise and waved his hand wildly, gesturing at where Tony was chattering on about his newest robotic creation to Steve. Steve was listening attentively and smiling, but every so often, he’d cast a stern look over his shoulder at Bucky and Natasha’s unabashed staring. 

Bucky was pretty sure Steve knew about and disapproved of their crush on his adopted brother. Probably because Steve was about as overprotective as a German Shepard of the people who he considered his family more than any personal grievance against Bucky and Natasha, but it still sucked that Bucky wasn’t able to pine over the boy he liked to his best friend. Not that he would’ve, because Steve was terrible at feelings-- the less said about his advice when Bucky was asking Natasha out, the better-- but it would’ve been nice to have the option.

“It has to be illegal for one person to be that cute,” said Bucky.

“He does look unfairly adorable in that sweater,” Natasha agreed. While she was less vocal with her affections, Bucky knew she was just as gone on Tony as he was.

“I just want to kiss him,” Bucky whined. 

“Dibs on kissing him first,” she teased. Bucky knew she was being serious, though; to Natasha, dibs were sacred.

He snorted. “You’re more optimistic than I am,” he said. “I don’t think either of us are going to be kissing him, Nat.”

“Who are you two planning to kiss?” Steve interrupted, ostensibly done with his conversation with Tony. He raised an eyebrow, looking a lot like his mother when she got to scolding. “It better not be Tony. He deserves better than to be used to spice up your relationship and then dumped.”

Bucky gaped at his best friend. “So  _ that’s  _ why you’ve been so weird!” he said, pieces falling into place. “Punk, we actually want to  _ date  _ Tony.”

Steve looked to Natasha for confirmation. Bucky wasn’t offended; Natasha had a far more trustworthy face, even if she could and did lie with the best of them. He could tell that she was being completely honest right then, though.

“Steve, we aren’t in it to hurt Tony,” she said. “If all we wanted was a little variety in our relationship, don’t you think we would’ve picked someone you wouldn’t kill Bucky for?”

“I would like it to be noted that I feel unfairly targeted, seeing as Natasha is an equal member of this relationship,” Bucky said dryly. “But she’s also right. We want a relationship with him: kissing, hand holding, all that sappy shit that they do in romance movies.”

“In that case, go for it,” Steve said, looking them both in the eyes. “But know that if you hurt him, I will break your legs. Natasha, I’ll… give you the patented Rogers look of disappointment.”

“You’re my best friend!” Bucky protested. “And why does Nat get off so easy?”   
  
Steve shrugged. “So I’ll do it with love, jerk,” he said. “Natasha scares me more than you do.”

“As I should,” Natasha said primly. Even curled up with Bucky as she was, she cut an intimidating figure. Bucky loved that about her. 

“If you two are going to ask him out, though, you’d better do it soon,” said Steve. “I heard a rumor that Hammer is going to ask him to prom.”

Bucky and Natasha exchanged a look.  _ Today?  _ his eyes asked.

_ Today _ , she responded with a twitch of her eyebrows.  _ During tutoring. I have a plan. _

Steve, as usual, was visibly baffled by their near-telepathic connection, but Bucky treasured it. It made a lot of things simpler, that was for sure. They were on the same wavelength, plan-wise, so Bucky didn’t even need to ask her for clarification. 

“Thanks, Stevie,” Bucky said to his best friend. He and Natasha stood. “But if you’ll excuse us, it’s time for our tutoring session. Is Tony upstairs?”

Steve nodded, so Bucky and Natasha took off hand in hand for the stairs. Tony had been tutoring them for months-- it was how their crush on the boy had started, actually-- in chemistry, since Bucky and Natasha were both barely scraping B’s, despite aceing their other classes. It had started right after Tony had moved in with Steve as a hesitant, nervous thing that happened in the library after school, but had quickly turned casual, the three of them meeting in Tony’s bedroom and munching on Sarah’s baking as they studied.

Tony’s door was open when they got to it, so Natasha flung herself on the bed without knocking, invading the space like it was her own, while Bucky followed at a more sedate pace. Tony didn’t startle to see them; in fact, he flashed them an indulgent smile as he pulled out his chemistry notes.

“Hey, guys,” he greeted. “Are you ready to start?”

Bucky looked at Natasha, letting her take the lead with her plan. She put on a flirty smile, pushing herself up on her elbows from her sprawl on the bed. Bucky’s mouth got a little dry at the sight of it.

“I don’t know, Tones,” she purred. “I think we’re feeling a little unmotivated today. You wouldn’t happen to have any sort of incentive for us, would you?”

Tony blinked, nonplussed. “Don’t tell Steve,” he said. Bucky leaned forwards in anticipation. But Tony just opened the drawer next to him and held out a box of cookies. “But Sarah made these this morning and I might’ve stolen them from the kitchen. Is that incentive enough?”

Bucky was only human, so of course he took a cookie. “I was thinking more along the lines of a kiss,” he said between bites. “Or multiple kisses, up to you. You’re the tutor, after all.”

“ _ Bucky! _ ” Tony hissed, absolutely scandalized. His face was an adorable shade of red. “Your girlfriend is  _ right there _ !”

“I am,” Natasha said placidly. “And I’m a little offended that he didn’t make it clear that I also require kisses as incentive.”

Tony spluttered for a solid minute. His mouth opened and closed as he tried to think of something to say. It was a little funny, Bucky could admit, but mostly cute. Tony finally settled on, “What the fuck? Is this some kind of joke? Because it’s not funny, guys.”

“It’s not a joke,” Bucky said, letting some of his seriousness show in his voice. “We like you.”

“We do,” Natasha continued, her eyes not leaving Tony’s. “And we’d like to take you on a date, if you like us, too.”

Tony watched them both for a long moment. Bucky had no idea what was going through his head; his poker face was impeccable. For a minute, Bucky worried that they’d made a mistake, misread all the signs, and any minute Tony was going to tell them he didn’t like them and never wanted to speak to them again. Next to him, Natasha was tense for presumably the same reason. They waited with bated breath for Tony to speak again.

“Let’s see how you do with chemistry today,” he said, a hint of a smile playing on his lips. “I’ll agree to your kiss incentive if you think it’ll help you study. How about one kiss for every question you get right? And if you both ace your tests, I’ll go out with you.”

Bucky had never been gladder to have studied in his entire life. He and Natasha had spent the previous night going over all of their chemistry notes, if only to impress Tony. He was positive they could do well in both the session and the test. Natasha was grinning like the cat who got the canary  _ and  _ the cream when she nodded.

“Fair deal,” she said, accepting for both of them. “Bucky, darling, close that door. I think we’re about to be pretty busy, and I don’t particularly want to be disturbed. Let’s start with orbitals, shall we?”

Natasha, of course, was right. They were  _ very  _ busy the rest of the evening, with Bucky and Natasha getting every one of Tony’s questions correct. And when they showed Tony their tests-- both marked with red 100’s at the top-- he didn’t hesitate to hold their hands on the way to the coffee shop for their first date.

**Author's Note:**

> comments and kudos make me happy :))
> 
> come talk to me on tumblr [@imposter-human](https://imposter-human.tumblr.com/)


End file.
